What are the keys to going super-low--driving distance, accurate irons, great putting? Using Riccio's Rules to study performance stats, it's clear that just about everything has to fall into place to post a sub-60 score.

Lou Riccio, who teaches rational decision making at Columbias Graduate School of Business and has served the USGAs handicap research team for three decades, takes on a lingering question from the U.S. Open: Did Phil Mickelsons decision not to use a driver make rational sense?